Among its many responsibilities, the U.S. Coast and Geodetic Survey was charged with observations of the earth's magnetic field. One of the instruments used for these measurements was this cosmic-ray meter, which detected the arrival of atomic particles from interstellar space at Earth’s surface.
means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.Among its many responsibilities, the U.S. Coast and Geodetic Survey was charged with observations of the earth's magnetic field.
One of the instruments used for these measurements was this cosmic-ray meter, which detected the arrival of atomic particles from interstellar space at Earth’s surface. These particles, called cosmic rays or astroparticles, are high-energy particles or clusters of particles that move through space at nearly the speed of light. They were first identified by Austrian-American physicist Victor Hess in 1912. Cosmic rays interact with the earth’s magnetic field, making them useful in the study of terrestrial magnetism. The earth’s magnetic field protects us from cosmic radiation and is the reason we are able to use compasses for navigation. In the early 1930s, the Carnegie Institution of Washington’s Department of Terrestrial Magnetism coordinated an effort to make continuous observations of cosmic rays at widely-spaced stations around the globe. By mid-1935, seven precision recording instruments were constructed under the direction of Dr. Arthur Compton at the University of Chicago. The design is known as Model-C, and its central component is a spherical “steel bomb”— a beach ball-sized ionization chamber filled with pressurized argon gas. The device has an outer shell that was filled with lead shot for radiation shielding. An onboard clock controlled the motorized scrolling of a roll of paper on which readings were made. A cosmic-ray meter, designed for making continuous records of cosmic ray intensity. Professor E.C. Wollan of the University of Chicago demonstrates the machine to Miss Alice Anderson at the National Academy of Sciences in 1934.Five Model-C instruments were deployed for permanent installation at magnetic observatories in the United States, Peru, Mexico, New Zealand, and Greenland . Serial number 1 arrived at the U.S. Coast and Geodetic Survey’s Cheltenham Magnetic Observatory in Maryland and began service in March 1935. Cosmic-ray observations at Cheltenham continued daily into the 1950s. By this time, urban development around the observatory had made the site unsatisfactory for sensitive scientific measurements. A new magnetic observatory was built near Fredericksburg, Virginia and on October 5, 1956, Model-C-1 was moved to its new home, where continuous measurements resumed days later.The instrument was used through the 1960s and into the 1970s, when it may have traveled with field parties. A paper tag affixed to the device indicates that a motor was replaced in August 1976. The instrument has multiple serial number labels, with one attached to the faceplate of the “electrometer” module. Curiously, this part is labeled not with the number 1, but 4. Model-C-4 operated near Mexico City, Mexico from 1937 to at least 1958. Perhaps the Fredericksburg instrument’s component needed replacement and was sourced from another of the group of seven. Three labels attached to the cosmic-ray meter, including a label reading “Model C No. 1” and a second label reading “Model C No. 4.”.In the years after NOAA’s formation in 1970, several of the U.S. Coast and Geodetic Survey’s functions went to NOAA’s National Geodetic Survey and responsibility for terrestrial magnetism was transferred to the U.S. Geological Survey. These agencies continue to operate at the Fredericksburg Magnetic Observatory, with part of the campus now serving as the National Geodetic Survey’s Testing and Training Center. The cosmic-ray meter remains at the Fredericksburg site, though now decommissioned. This unique instrument, detecting minute particles from far beyond our earthly shores, provided decades of faithful service and helped grow our understanding of earth’s magnetic field.Have an idea for an artifact, photo, or document from NOAA’s history that you think we should feature in “Friday Finds!”? Send an email with a description and, if possible, a photo to
Heritage Heritage History Friday Finds National Geodetic Survey
United States Latest News, United States Headlines
Similar News:You can also read news stories similar to this one that we have collected from other news sources.
Fort Bend Judge Could Find Out Friday Who’s Presiding Over His Felony CaseFort Bend County Judge KP George’s court appearances are ramping up as the chief elected official was granted a continuance on a misdemeanor case last week and will find out Friday if a presiding officer from another jurisdiction will hear his felony case. George is charged with misdemeanor identity misrepresentation,...
Read more »
Friday Find: Hot off the PressThis copper plate printing press was in operation by the U.S. Coast Survey, the Environmental Science Services Administration, and then NOAA, from 1851 through 1976.
Read more »
Dementia Rates Show Generational DecreaseDementia rates among older adults are significantly lower among more recent generations, particularly among women, across the US, Europe, and England, a new study shows.
Read more »
Tracing the Roots: The Story of Juneteenth premieres Thursday at 7 p.m.Juneteenth marks June 19, 1865, when enslaved people in Galveston, Texas, learned of their freedom. Though rooted in Texas, the day holds national significance.
Read more »
Live updates: 11 campers among 41 people missing; 28 kids among nearly 80 killedSearch and rescue efforts continue Sunday as the death toll from flooding in Central Texas grew to 69 overnight, including at least 21 children.
Read more »
11 campers among 41 people missing; 28 kids among nearly 81 killedSearch and rescue efforts continue Sunday as the death toll from flooding in Central Texas grew to 69 overnight, including at least 21 children.
Read more »